Selected Quarterly Financial Data (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
	Mar. 31, 2013	Dec. 30, 2012	Sep. 30, 2012	Jul. 01, 2012	Apr. 01, 2012	Jan. 01, 2012	Oct. 02, 2011	Jul. 03, 2011	Mar. 31, 2013	Apr. 01, 2012	Apr. 03, 2011
Quarterly Financial Information Disclosure [Abstract]
Sales	$ 87,601,000	$ 85,527,000	$ 87,160,000	$ 90,099,000	$ 83,210,000	$ 84,160,000	$ 87,870,000	$ 88,594,000	$ 350,387,000	$ 343,834,000	$ 297,641,000
Gross profit	14,307,000	8,126,000	19,196,000	15,307,000	13,512,000	15,679,000	18,750,000	17,927,000	56,936,000	65,868,000	61,902,000
Selling, general, and administrative expenses	8,307,000	7,617,000	7,455,000	8,227,000	7,895,000	7,163,000	7,844,000	7,857,000	31,606,000	30,759,000	29,940,000
Operating income	6,000,000	509,000	11,741,000	7,080,000	5,617,000	8,516,000	10,906,000	10,070,000	25,330,000	35,109,000	31,962,000
Income from continuing operations, net of tax	4,165,000	1,348,000	7,230,000	4,365,000	3,273,000	5,285,000	6,717,000	6,353,000	17,108,000	21,628,000	20,314,000
Income from discontinued operations, net of tax	0	0	0	18,000	232,000	267,000	184,000	374,000	18,000	1,057,000	0
Net income	4,165,000	1,348,000	7,230,000	4,383,000	3,505,000	5,552,000	6,901,000	6,727,000	17,126,000	22,685,000	20,314,000
Basic earnings per share (usd per share)	$ 0.40	$ 0.13	$ 0.69	$ 0.42	$ 0.34	$ 0.54	$ 0.67	$ 0.65	$ 1.64	$ 2.19	$ 1.98
Diluted earnings per share (usd per share)	$ 0.39	$ 0.13	$ 0.69	$ 0.42	$ 0.34	$ 0.53	$ 0.67	$ 0.65	$ 1.62	$ 2.18	$ 1.96
Legal settlement				3,200,000
Multiemployer pension plan withdrawal charge		$ (7,200,000)							$ 7,210,000	$ 0	$ 0